Acta Theriol DOI 10.1007/s13364-012-0085-x ORIGINAL PAPER Evidence for a differentiated chromosomal race north of classical south European refuge areas in the garden dormouse Eliomys quercinus Roland Libois & Maria Graça Ramalhinho & René Rosoux Received: 5 October 2011 /Accepted: 12 June 2012 # Mammal Research Institute, Polish Academy of Sciences, Białowieża, Poland 2012 Abstract The dormouse Eliomys quercinus is a forest rodent hybrid between these two races (2N049) was found in Vendée. undergoing long periods of winter hibernation. The species These facts reveal that neither the Pyrenees nor the Alps con- presents a surprisingly large diversity of chromosomal races, stitute a biogeographic barrier to the dormouse and strongly which geographic distributionwasshownrecentlytopredate suggest that the present population of northern France derives the Pleistocene glaciations. Previously reported data on the from a postglacial recolonisation movement initiated in the karyotypes of the garden dormouse in France come from the southernmost regions of France or in the Rhône valley. northeast of the country, where the 2N050 race occurs. New data are presented from specimens trapped near the Atlantic Keywords Garden dormouse . France . Distribution . coast (departments of Vendée and Charente-Maritime), in the Karyotypes . Hybridization Pyrenees, the Alps and in the Massif Central. The French Alpine chain, close to the Italian border, is inhabited by the 2N054 race. A karyotype with 2N048 chromosomes, of Introduction Iberian type, is found north of the Pyrenees, near the central Atlantic coast and also in the south of the Massif Central, The postglacial recolonisation patterns of forest rodents whereas the 2N050 race occurs in the north of the massif. A have been extensively studied in recent years (Deffontaine et al. 2005; Michaux et al. 1998, 2004; Nieberding et al. Communicated by: Mieczyslaw Wolsan 2005). These studies demonstrated that most rodents sur- vived the cold periods of the Quaternary in temperate south- R. Libois (*) Unité de recherches zoogéographiques, Bâtiment 22, ern refuges including Spain, Italy and the Balkans. This Université de Liège, pattern may not be applicable to species displaying winter Boulevard du rectorat, 27, hibernation, and increased tolerance to cold temperatures, 4000 Liège, Belgium for which more northerly refuge areas might be expected. e-mail: [email protected] The garden dormouse (Eliomys quercinus) is a useful model M. G. Ramalhinho species to test this hypothesis, sharing an ecological niche CESAM (Faculdade de Ciências), with rodents for which data are available, but having exten- Museum National de Historia Natural e Ciência, sive periods of winter hibernation. Moreover, it has been Universidade de Lisboa, Rua da Escola Politécnica, 58, previously shown that this species exhibits allopatric differ- 1268-102 Lisbon, Portugal entiated karyotypic races (Cristaldi and Canipari 1976; M. G. Ramalhinho Filippucci et al. 1988b; Zima et al. 1994). The differentia- e-mail: [email protected] tion of these karyotypic races predates the Quaternary peri- od and likely took place about 4 million years ago (Perez et R. Rosoux al. 2012). During the Pliocene period, a rather warm climate Museum d’Histoire Naturelle, rue Marcel Proust, 6, prevailed in Europe (Fauquette et al. 1998), and the Eliomys 45000 Orléans, France genus was well distributed in Spain, in southern France, in R. Rosoux Greece (Kowalski 2001), in northern Italy (Verona: Sala e-mail: [email protected] 1996) and in Sardinia (Kotsakis 1986). Thus, the dormouse Acta Theriol chromosomal races were confronted to the contrasted cli- (Murariu et al. 1985), Russia (Graphodatsky and Fokin 1993) matic conditions that started with the Quaternary period. and the western Mediterranean islands, except Sardinia. The This dormouse is currently found in forests of pine, larch and animals with 50 chromosomes are distributed from north- oak and in mixed coniferous and deciduous woods, orchards, eastern France to Germany, Austria and Czech Republic and vineyards, parks and villages, from sea level to the upper tree are present in Sardinia (Cristaldi and Canipari 1976;Zimaetal. limit (currently to 2,300 m in the Alps or the Pyrenees, but still 1994, 1997). A Swiss form with 2N052 was first reported by higher in southern Spain or Morocco at 2,500 and 2,800 m, Matthey and Renaud (1937) and its presence confirmed later by respectively). It also lives in Mediterranean scrub, if not too Renaud (1938). Unfortunately, the location of the capture site dense, and utilises stony or rocky environments, colonising old (s) of the specimens analysed was not given. However, it seems buildings, ruins, dry stone walls as well as mountain boulders, that Renaud trapped small rodents in the “district de Lausanne” karstic habitats, old quarries or cliffs. Some populations live in (op. cit., p. 350). Later, this form has been found in the Alps, forested sand dunes (Marismas del Guadalquivir; northern from the Valle d’Aosta to the eastern part of the chain (Cristaldi Belgium). Throughout its distribution, it is found in close prox- and Canipari 1976; Filippucci et al. 1988b; Ramalhinho and imity to humans, in farms, huts, storehouses or attics (after Libois 2005). Another form with 2N054 ranges from Liguria, Ognev 1963;Storch1978 and personal observation). near the Mediterranean coast, to the Valle d’Aosta and the The systematics of the genus Eliomys is still a question of upper Rhône valley (Cristaldi and Canipari 1976; Filippucci debate and long-standing conflicting opinions. No less than 28 et al. 1988b;Zimaetal.1994). names have been proposed since 1766 (Holden 1993), and Until now, there have been no reports of contact or hybrid Miller (1912) recognised five extant species in Europe alone, zones between these different races, with the exception of whereas Ellerman and Morrison-Scott (1951) reduce the num- the region of the Gran Paradiso where Cristaldi and Canipari ber of species to two: E. quercinus from Europe and north (1976) observed the sympatry of both Alpine forms (52 and Africa and Eliomys melanurus from “south-west Asia” (i.e. 54 chromosomes). the near-east). More recently, various authors have considered Surprisingly, in France the few data published have all that a single species, formed by three distinct lineages, or reported a diploid number of 2N050 chromosomes, except subspecies, is present in Europe: the “quercinus”, “lusitanicus” in Corsica where it is 48 (Italian race; Table 1;Orsini1987). and “melanurus” lineages (Corbet 1978; Kahmann and Thoms However, all the animals studied were trapped in the central 1981; Niethammer 1959;Storch1978). These lineages are and north-eastern part of the country, where a diploid number distinguished on the basis of the coloration pattern of the tail. of 50 would be expected given the distribution of this chro- However, this viewpoint is not universally accepted mosomal race in neighbouring countries (Fig. 1). No analysis (Nadachowskietal.1978; Nader et al. 1982). From karyolog- has been done on dormice living either on the northern slopes ical analyses and electrophoretical comparisons, Filippucci et of the Pyrenees nor in the French part of the Alpine massif, i.e. al. (1988a, c) concluded that two distinct species existed, i. e. E. in the vicinity of other chromosomal races. quercinus in Europe, including the Mediterranean islands, and Recently, the postglacial recolonisation of Western Europe E. melanurus in northern Africa (N046 chromosomes) and the has been studied in several species, showing the significance near-east (N048 chromosomes). of the Alps and of the Pyrenees on their phylogeographical Krystufek and Kraft (1997) collected skull samples pattern (Hewitt 1999; Michaux et al. 1998; Taberlet et al. throughout the north African, near-eastern and west 1998). This paper presents new information on the French European parts of the distribution of the dormouse and distribution of Eliomys chromosomal races and discusses the concluded that animals from the near-east are distinct from role of these mountain chains as biogeographical barriers. all the other ones. The border between quercinus’ and melanurus’ distribution ranges lies somewhere in Libya, between Cyrenaica and Tripolitana. Therefore, the Eliomys Methods genus contains two species, but the question of their African distribution is still under debate. Animals were live trapped in LFA Sherman traps (7.5×8.9× The existence of different morphotypes and cytotypes in 22.9 cm) baited with a sardine and flour mixture in southern the European garden dormouse has long been recognised. France, from the Atlantic coast to the Alps, and cytologically However, as cytological studies progressed, it became evi- analysed. Microscope slides for observation of the chromo- dent that these morphotypes did not fully correspond to the somes in somatic metaphases were prepared by direct treatment karyological characteristics (Cristaldi and Canipari 1976; of the bone marrow (Baker et al. 1982). The G banding was Krystufek and Kraft 1997). obtained using Seabright’s technique (1971). The diploid num- In Europe, four chromosomal races have been found. One, ber (2N) and the morphological chromosome characteristics with 2N048 is distributed in the Iberian peninsula, central and were analysed using a Leica Q500 image analyser and Leica southern Italy, Croatia (Vujosevic et al. 1993), Romania Chantal and Qwin software. Acta Theriol Table 1 Localities and geographical coordinates